Question

if oxygen atom in watér is replaced by sulphur then change in bond angle equal to .....​

Answer 1

Answer:

The bond pair-bond pair is smaller in magnitude, still the bond pair-bond pair repulsion (steric effect) between the hydrogen in water is bigger than in hydrogen sulfide because oxygen is smaller. Going down the group the bond pair-bond pair repulsion decreases in magnitude much faster than lone pair-bond pair, therefore the smaller angle. Bigger size, in this case wins over smaller electronegativity (which would imply the opposite). If the central atom becomes big enough, the bond angle won't change much downwards.